Helical broaching fixture



All@ l, 1950 H. H. G01-BERG 2,517,104

HELICAL BROACHING FIXTURE l Filed March 5, 1947 2 Sheets-Sheet-l iva/f/VEKS,

Aug. l, 1950 Filed March 5, 1947 H. H. GOTBERG HELICAL BROACHING FIXTURE 2 Sheets-Sheet 2 der 56. The shank portion 51 of a lock pin, generally indicated at 59, is received inthe aperture 55 and a coil spring 6|, surrounds the shank 51 and is positioned within the enlarged portion of the aperture 53 The lock pin-'shank-51 is provided with a laterally extending pin 63 adjacent the lower end thereof aaginst which the lowe'rv end `of the spring abuts. An annular ring 65 is secured'to the top surface of the boss 53 by means of screws 51.' The inner periphery 59 of the ring 65 'is of a smaller diameterthan the'diameter of the enlarged portion of the Aaperture 55 so as to retain 'the upper end of the coil spring 6|. The upper end of the shank 51 terminates in an enlarged cylindrical hand grip portion 1|, which portion abuts against the top surface of the annular ringl651to limit the downward movement of the lock pin 59. y

The 'main cover member 43 is provided with three laterally spacedapertures 13, 15, and 11, one of which is adapted to be aligned with the lowerend of the lock pin 59 so as to receive'the lower end of the lock'pin `shank 51 when the member 49 isl swung about pin 41 to the correspondingp'osition, as will behereinafter brought out. Theyswinging member 49 is formed adjacent the rear 'end thereof with a depending portion 19, one side of which slidably engages a cylindrical side wall portion of the housing |1 at 99. This portion 19 of the member 49 is provided with a vertical bore 8| in which is fitted a pin 83 having a head 33 on the upper end thereof which is received in a counterbore 84 at the upper end of the bore 89. Adjacent the lower end of the pin the-adjusting member depending portion 19 is provided with a slot 85. Positioned within the slot 85 Aand pressed on the pin 82 is an antifriction bearing 81. Fixedly mounted on the outer race of the bearing 81 is a gear 89 which is constantly in mesh with the gear 36 mounted on the chuck'shank Secured to the top surface of the main'covcr 43 is an auxiliary cover'member 9|, The cover 9| is secured to the main cover 43 by means of a plurality of screws 93. The underside of the cover 9|, forwardly of the rear end of the fixture is in sliding engagement with the upper surface of the sliding member 49. The forward end of the cover 9| is of an arcuate shape, as at 95, as can be seen in Fig. 1, and abuts against the arcuate shoulder on the forward end of the sliding member 49. Forwardly of the gear 89, the member 49 is 4provided with a tapped aperture 91 in which is threaded a stud 99, the upper end of which projects through a slotted aperture |9| in the upper cover 9|. A nut |03 is threaded on the upper end of the stud to hold the upper cover through. The lower end of each lead bar passes through the aperture 3 vand is rigidly connected to the bracket by means Vof a key ||5. The extreme lower end of each lead bar is threaded, as at H1, and a nut ||9 is threaded thereon to lock and position each of the lead bars with respect to the broaching machine. The upper end of each lead bar (not shown) is similarly fixedly connected to the breaching machine.

Each of the lead bars |95 and |91 are provided with a continuous helical spline |2| extending along the entire length thereof, but the splines of the two bars are of different helix angle. Thus, the splines on the lead bar |55 may be of different angle and the same hand as those on the lead bar |91 or they may be of opposite hand and either the same or different angle. Each of the lead bars are identically constructed, except for the helix angleV of the splines, and each is similarly mounted in the xture and carries the same operating parts thereon. rlherefore, only the mechanism associated with the lead bar |05, which is shown in detail in Fig. 3, will be described, it being understood that similar part numbers apply to the operating parts for both lead bars. l

` A shouldered nut |25 having helical splines on the inner' periphery thereof adapted to engage the helical splines on the lead bar, surrounds the lead bar and the shouldered upper end thereof rests on a recessed upper surface |21 of the main cover member 43. The upper surface of the housing member l1 adjacent the lead bar aperture is recessed, as at |33, and a gear |35 is positioned therein and keyed to the nut |25 at |31. The gear is rotatably supported in the housing by means of an antifriction bearing |39, the outer race of which is received in a recess |4| in the housing. A conventional oil seal |43 is received in a recess |45 in the bottom face of the housing to prevent leakage of oil. The gear |35 is rotatably supported in the lower cover member 43 by means of an antifriction bearing |41, the

y outer race of which is pressed into a recess |49 bar aperture, is recessed as at |53 and an oil seal various sized breaches4 |54 is received therein and abuts the upper surface of the washer |5|. The lower end of the nut |25 is threaded as at |55 to receive lock nuts |51 which lock the nut 25 in position with respect to the gear |35. It will be noted that the gears |35 on each of the lead bars |95 and |91 are adjacent to the gear 89 mounted in the member 49 and are in the same plane with the result that by swinging member 49, the gear 89 can be meshed with the gear |35 on either of the lead bars, as desired.

In order to lubricate the gears |35 on each of the lead bars and lill, conventional grease iittings ll are provided which project outwardly from the lower cover member and communicate with each of the gears |35.

The lower end of the chuck l5 is provided with a recess |33 therein, in which is received a broach puller |55 which is interchangeable to receive The broach puller |65 is locked in position in the chuck by a key |51 which is xed by screws 13 in. a recess |39 in the chuck body and which has a tongue l1! that projects into an annular recess in the shank of the broach.

In the operation, if it is desired to broach straight splines or other forms of openings in the workpiece, the sliding member 49 is positioned so that the lock pin 59 will be received in the central aperture l5 in the lower cover member. When in this position, as illustrated in Fig. 1, the gear 89 will be in mesh only with the gear 36, which is connected to the chuck and will be out of engagement with the gears |35 on both of the lead bars. Therefore, no rotation of the chuck will occur upon movement of the sliding ram Il of the breaching machine.

If it is desired to breach splines of the type produced by lead bar 695, the lock pin 59 is pulled upwardly so as to be out of engagement with the lower cover member d3 and the member 49 is moved to the right so that the lower end of the lock pin 59 will be received in the aperture 'Vl in the lower cover member and the gear 89 will mesh with the gear its on the lead bar [05, as well as the gear 36 on the chuck.

If it is desired to breach splines of the type produced by lead bar lill', it is merely necessary to pull the lock pin upwardly and swing the member 49 to the left so that the lower end of the lock pin will be received in the aperture 73 in the lower cover member. The gear 89 will then be in mesh with the gear E35 0n the lead bar 10'! as well as the gear 35 on the chuck.

Due to the cover arrangement of the fixture, it con be easily repaired, or any worn out parts can be replaced. By removing the upper cover 9 l the sliding member t9 will be exposed, and can be lifted from the xture. The lower cover plate can then easily be removed and any worn out parts can be replaced easily and quickly.

It can therefore be seen that this fixture is adapted to be mounted on any type of conventional pull broach machine and will allow by simple adjustment, broaching of either one of two types of helical splines, or straight openings, in the workpiece. It will be understood that the machine is equally adapted to broach internal gears or any irregularly shaped opening having a helix angle.

What is claimed is:

1. A broach moving fixture for broaching helices and the like including a frame, holding means carried by the frame for xedly supporting in parallel relation a plurality of lead bars having diierent helical splines, a broach moving head slidable lengthwise with respect to said lead bars and adjacent such lead bars, a broach moving chuck journaled in said head on an axis parallel to said lead bars, a pair of traveling nuts carried by said head. one of said nuts being threadedly intermeshed with each of said lead bars, a gear drivably connected to each nut, a gear drivably connected to said chuck, and means for selectively establishing a driving connection between said last gear and either of said rst gears in order to broach different forms of helical openings, comprising a shift member also carried by the head and movable to selectively and alternatively make and break driving connections between said gear connected to the chuck and either of said rst gears.

2. A broach pulling xture for helical breaching, including a pair of stationary parallel helical lead bars having helical splines of different helix angles, a breach pulling head comprising a housing slidable lengthwise with respect to said lead bars and having openings through which the lead bars project, a broach pulling chuck having a shank journaled in said housing on :an axis parallel to said lead bars, a pair of splined nuts on said lead bars respectively and located within said housing, a gear on each nut, a gear on said chuck shank, a member pivotally mounted within said housing on an axis concentric with said chuck shank, a gear journaled on said member and in constant mesh with the gear on said chuck shank, and means for swinging said member into and locking the same `in any one of two positions, in one or" which the gear on said member meshes with the gear on one cf said nuts, and in the other it meshes with the gear on the other nut.

3. A breach pulling nxture for helical broaching including a pair of stationary parallel helical lead bars having helical splines of different helix angles, a broach pulling head comprising a housing slidable lengthwise with respect to said lead bars having openings through which the lead bars project, a broach pulling chuck having a shank journaled in said housing on an axis parallel to said lead bars, a pair of splined nuts on said lead bars respectively and located within said housing, a gear on each nut, a gear on said chuck shank, a member pivotally mounted within said housing on an axis concentric `with said chuck shank, a gear journaled on said member and in constant mesh with the gear on said chuck shank, and means for swinging said member into and locking the same in any one of three positions in one of which the gear on said member meshes with the gear on one of said nuts, in the second of which the gear on said member meshes with the gear on the other nut and in the third, it is out of mesh with both of the gears mounted on said nuts.

ll. A xture as defined in claim 1 wherein said shift member comprises a frame carrying an idler gear constantly meshing with the gear connected to the chuck, said frame` being swingable about the axis of said gear connected to the chuck to move the idler into and out of mesh with either of said gears connected to the nuts.

5. A xture as defined in claim 1 wherein each of the rst two mentioned gears is concentric with one of the nuts and the last gear is concentric with the chuck, said shift member comprising a frame carrying an idler gear constantly meshing with the gear connected to the chuck, said frame being swingable about the axis of said chuck to move the idler into and out of mesh with either of said gears connected to the nuts.

HARRY H. GOTBERG.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,023,593 Pool Apr. 16, 1912 2,043,596 Rovick June 9, 1936 2,158,720 Hart May 16, 1939 

